Co-generation – Ashley


Cogeneration and CHP, also known as Combined Heat and Power, is the process of generating two types of energy, usually heat and electricity, from one source(1). Often one type of energy has is the byproduct of the other, cogeneration puts both energies to use as oppose to letting one go to waste.  For example, often when one generates electricity, heat is often a byproduct, rather than releasing the heat back into the environment, the heat is can be used in a nearby building.

Cogeneration has many positive values such as having a high efficiency, which can actually be up to 30% more efficiency than traditional power plants which only capture one type of energy(2).  Using both products also makes cogeneration more environmentally and economically friendly since it reduces CO2 emissions and reduces costs needed to create both forms of energy(3).

Cogeneration can work for systems of almost any size, from an industrial plant to a small generator, and can run on many different types of fuel such as natural gas, heating oil, biomass, biogas, biodiesel and geothermal(3). However, this is a renewable resources course so this blog will focus on bioenergy cogeneration as well as cogeneration in Europe, though there could be some comparison to the U.S.


  1. American DG Energy. “Cogeneration/Combined Heat and Power (CHP).” Web. 16 May 2012. <;
  2. Yale Office of Substantiality. “What is Cogeneration?” Web. 16 May 2012. <;
  3. CogenEurope. “What is Cogeneration?” Web. !6 May 2012. <;


CHP or Combine Heat and Power seemed to be standard in both countries we visited, as it should up on multiple sites and tours we went on. In Germany many of the anaerobic digesters where attached to a CHP generator, and often the heat generated would not only be used to keep the digester at the correct temperature but be sold to nearby places to be used, such as green houses, nearby homes, or when we were at the Munich Zoo digester the heat was used at there at the zoo. Almost all the anaerobic digester we visited had a CHP generator, expect for one of the UTS anaerobic digesters.

A picture of a CHP generator at the waste plant in Germany.

In Sweden we were able to visit a Combine Heat and Power plant which provide heat and electricity to a nearby town all year around. In the summer, such as now, and the town did not need as much heat, the heat generated would be used to make wood pellets which could be sold. In the winter the heat would go back to warming the town and now wood pellets would be made. This CHP plant was huge and had an efficiently way to constant use the heat and electricity the plant generated.

Combine heat and power is a proficient and friendly way to create and use two type of energy for the price of one. It is also very applicable in the Michigan and other parts of the United States where there are cold winters and towns could use the heat as well as the electricity. One of the challenges of combine heat and power is what to use the heat for in summer months when people use less heat; however heat could either be used towards other products or used towards cooling. CHP is an agreeable way to create power and heat and raise efficiently levels of a plant.


One response to “Co-generation – Ashley

  1. The concept of combined heat and power was prevalent at almost every site we visited. It was interesting to see how these industries were able to maximize efficiency and reduce waste. Even though heat generation was not the primary goal of most of the plants that we visited, they produced it in significant supply and were able to heat many homes in the surrounding area. The Skelleftea plant that we visited produced electricity, heat, and pellets. The versatility of industry and the ability to diversify one’s product stream will be necessary for businesses to thrive in the coming years.

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